Most modern electronic equipment require a power supply to provide a direct current (DC) operating potential to the electronic components contained therein. Common types of electronic equipment which use DC power supplies include cell phones, personal computers, energy systems, telecommunication systems, audio-video equipment, consumer electronics, automotive components, and other devices which utilize integrated circuits, semiconductor chips, or otherwise require DC operating potential. Most, if not all, semiconductor components require a low voltage DC operating potential.
Not all semiconductor devices or electronic components operate with the same DC potential. Some integrated circuits (ICs) or discrete semiconductor devices require a higher DC supply voltage than others. A common approach in electronic systems requiring multiple DC operating voltage levels is to convert a base DC operating potential to other voltage levels. For example, the battery or main power supply to the electronic system may provide 3 volts DC. One or more DC/DC boost converters within the electronic system increase the voltage level to say 5 volts DC or 12 volts DC to supply power to certain components within the system.
The DC/DC boost converter uses an inductor or coil having a first terminal coupled to the converter input and power metal oxide semiconductor field effect transistor (MOSFET) coupled between a second terminal of the coil and ground. The conduction through MOSFET is controlled by a pulse width modulated (PWM) controller. The PWM controller turns on the power MOSFET to enable a current conduction path through the coil and thereby store energy in the coil. When the PWM controller turns off the power MOSFET, the energy stored in the coil is transferred through a Schottky diode to an output of the DC/DC boost converter. The output voltage of the converter is used to generate a feedback signal to the PWM controller to control the on-time of the power MOSFET and regulate the DC output voltage of the boost converter.
The power MOSFET and Schottky diode are typically discrete components in the DC/DC boost converter. In some electronic systems, such as cellular phones, space on the printed circuit board (PCB) is a premium. As cell phones reduce in feature size, the space required for discrete components becomes a design issue. In addition to surface area limitations, the need for low profile and small footprint semiconductor devices continues to grow as cell phones become thinner and smaller in design.
A need exists for semiconductor devices and packages that are compatible with electronic systems having limited surface areas and low profiles.